A 28-year-old woman has been delivered to a hospital with acute pain in the lower abdomen. There was a brief syncope. The delay of menstruation is 2 months. Objectively: the patient has pale skin, BP- 90/50 mm Hg, Ps- 110/min. Lower abdomen is extremely painful. Vaginal examination reveals uterus enlargement. Promtov's sign (pain during bimanual gynecological examination) is positive. Right uterine appendages are enlarged and very painful. Posterior vault hangs over. What is the most likely diagnosis?